Javascript return not breaking out of function

I have a javascript function which checks to see if an artist exists in an XML file:

function artistExists(artist) {
// get data from artists.xml 
$('.loading').show();
$.get(artists_xml, function(xml){  
    $('.loading').hide();
    $(xml).find('artist').each(function(){
        if ($(this).find("ar_artist").text() == artist.val()) {
            alert ('artist exists');
            return true;
        } //end if
    });  // end each
    alert ('artist does not exist');
    return false;
}); // end .get function
} // end of artistExists function

Am I right in thinking that the 'return true' line should quit execution of the function? I thought it would, but after finding a record and running the first alert execution continues to the failure alert at the bottom.

What am I doing wrong please? Thank you.